When laser light is reflected from a roughened surface or transmitted through a roughened transparent surface, the visual experience is an illuminated field covered with a "grainy", gaussianly distributed speckle pattern. Changes in the refractive condition of the eye by external lenses or natural refractive error have very small effects upon the size and spatial distribution of the speckle and no effect upon the "sharpness" of the speckle pattern. Spatial modulation of even small (3 min arc) speckle patterns may be used to evoke unusually large cortical evoked responses (LASCERs). We show that LASCERs are easily produced and that speckle in the 2-5 minutes of visual arc range are easy to generate. This proposal deals with the programmatic development of our understanding of laser speckle and its subsequent development as a "refraction free" visual stimulus which has potential value for the evaluation of macular function in eyes which cannot be fully corrected due to patient cooperation or opacities. The research during the first year will include (a) the control of speckle size and contrast for clinical use, (b) comparison of predicted parameters of speckle with those subjectively experienced in normal eyes, (c) evaluations of healthy eyes to determine the most efficient speckle parameters. Years II-IV will see expansion of the research into the clinic where laser cortical evoked responses (LASCERs) evoked by a range of speckle sizes and contrasts will be used in patients with various refractive errors and healthy eyes to measure response dependence as it varies with the age over 6 decades. A number of patients scheduled for nuclear cataract surgery will have LASCER series performed and the cataract characterized by the method of "lens light backscatter." During follow-up visits, LASCERs will be recorded and post-operative, best corrected acuities will be compared to the pre-operative LASCER results.